Washington Nationals Player Preview: Patrick Corbin

Patrick Corbin is entering the fifth year of a six year deal given by the Nationals back in the 2019 offseason, and it very well could be the most important of his career.

Continuing with our player preview series, today we are taking a look at Patrick Corbin. I know what you're thinking - what is there left to say? We all know what the Patrick Corbin experience has entailed over the past few seasons, basically since his contributions in the 2019 postseason run. Simply put, he's been the worst pitcher in baseball. And it is not due to a major injury or significant change in circumstance; he just hasn't been good. But we are going to do our best not to focus on that.

Instead, we are going to try to identify a way back to consistency for Patrick Corbin. This isn't to say this is what the Nationals & Corbin are working on or even considering, but rather identifying a possible reality in which Patrick Corbin could be a valuable starting pitcher again for this team.

To identify a way forward, we have to know where Corbin has gone wrong. According to Baseball Savant, Patrick Corbin ranked in the bottom 5 percentile in several categories last season, including Average Exit Velocity, Expected Batting Average and Slugging, Hard Hit Percentage and Barrel Percentage. The important category to note is Hard Hit Percentage. Last year, Patrick Corbin allowed a hard hit ball on 45% off balls in play, which was nearly 7% higher than his 2019 campaign and nearly 10% higher than 2018. It was also nearly 10% higher than the MLB average. So why is Corbin suddenly getting hit so hard? The short answer falls to one common denominator: his slider.

In 2018 and 2019, Patrick Corbin had one of the most devastating sliders in baseball. It was part of the reason the Nationals decided to outbid teams like the New York Yankees for the services of Patrick Corbin; analytics suggested his slider would age well (not that the Nationals have ever been the most analytically inclined franchise). 2019 backed that up, as Corbin had a whiff percentage of 51.4% on his slider, which meant hitters swung and missed at his slider more than half of the time. In 2021, that number was down to 40.7% and down to 36.9% in 2022.

Corbin was really able to ride his slider to much success in 2018 and 2019, as his second most used pitch, his sinker, has never been more than an average pitch. He was just able to use it well, mixing it with his slider to induce more swings and misses. Without the devastation in his slider, his sinker, 4 seam fastball and other pitches went from average, to much, much less effective.

So what made Corbin's slider so effective in the first place? Despite the pitch name, it actually wasn't the horizontal movement, but rather the vertical movement. Most baseball fans associate vertical movement with a curveball, but Corbin's slider was the best of both worlds. In 2019, Corbin's slider averaged 1.3 inches more of vertical movement than the league average. In 2022, it averaged 0.9 inches less than the league average. This is despite the same average MPH on the pitch (81.7 mph) in both seasons. That's over 2 inches less in difference in vertical movement. Long story short: his slider is staying flat and it's becoming much easier for hitters to either take or tee off on. He's also tending to miss over the middle of the plate more often rather than burying it low and in to right-handed hitters, hence the teeing off by opposing hitters. For another advanced metric on Corbin's slider, the pitch had a -26 run value back in 2019 and a 23 run value in 2022. Quite the stark contrast.

So how do they fix the slider? Well that is up to the Nats to figure out. It could be as large as changing his arm angle and other mechanics or as small as tweaking the pitch grip. From the television view, it does seem like his arm slot is a bit lower than in previous years, but it could also be the camera angle. They'll assuredly try many courses of action this spring and as the season rolls on. His spin rate on his slider has decreased each season since 2019 and is more than 200 RPMs less now than it was then. Perhaps he was one of the many pitchers using sticky stuff. I don't want to assume, but it would also be naive to believe that the sticky stuff usage was isolated to a select few pitchers. Or it could have nothing to do with the sticky stuff, or lack thereof, at all.

What I know is this: Patrick Corbin used to have one of the best pitches in baseball. He has used that pitch to much success in his career and it would not be unreasonable to believe he discovers some of what he lost in that pitch this season. It could be wishful thinking, and maybe it is, but if Corbin is able to do that, I think we could see a much better result from him in 2023. To his credit, he's at least been able to stay healthy over the past few seasons - something the Nationals need their pitchers to do this season. He didn't even have so much as a phantom trip to the IL to press reset after a long string of bad outings.

It was a lost season all around in 2022, but something that was overlooked was that Patrick Corbin had six starts from mid-August to mid-September in which he averaged 6.1 IP per start and had an ERA of 3.41. He ended up injuring his back in his next start, and having a poor performance in his subsequent start 12 days later, which ended up being his final start of the season. But all in all, Corbin had an under-the-radar strong finish to the season. If he can have an ERA around 4 this season, I think all Nationals fans would be more than happy.